Non-steroidal, anti-inflammatory drugs (NSAIDs), have a problem of causing serious side-effects such as gastrointestinal tract distress or nephro-toxicity. NSAIDs inhibit the activity of cyclooxygenase (COX), which is an enzyme involved in prostaglandin G/H synthesis, resulting in the inhibition of the biosynthesis of prostaglandins not only in inflammatory loci but also in stomach and kidney. It has been found that COX exists in two forms: COX-1 and COX-2, Cell, 83, 345, (1995).
COX-1 is expressed in normal cells and controls the function of stomach and kidney, while COX-2 is induced by mitogens or cytokines in inflammatory sites where inflammation and other immunoreactions occur, J. Biol. Chem., 271, 33157(1996).
To avoid the toxicity of NSAIDs due to the inhibition of coexisting COX-1, selective inhibitors of COX-2 have been investigated. The selective COX-2 inhibitors have anti-inflammatory action, pain-relieving action, and/or antipyretic action; with less side effects such as bleeding in the gastrointestinal tract. COX-2 inhibitors may show anticancer activity, and lower the induction of asthma in asthmatic patients who are sensitive to conventional NSAIDs. These selective inhibitors of COX-2 may also be used in treating Alzheimer's disease and osteoporosis of women after menopause.